Damage formation and annealing studies of low energy ion implants ...

4.5 Sample production
Samples have been implanted using an Applied Materials Quantum LEAP
implanter (12) at AMD Dresden and Applied Materials (UK). Some samples and have
also been implanted at Salford University using the ultra low energy (ULE) implanter
(11). The principle behind the two implanters is the same and the Salford implanter is
described here in section 4.5.1. Major differences between them are the size of sample
that can be implanted and sample throughput. The implanter at Salford is a research tool
and can only implant small samples of approximately 12 × 12 mm. The Applied
implanter is a manufacturing tool and hence wafers of 200mm or 300mm diameter were
implanted. Unless otherwise stated, the implants used in this thesis were implanted at
AMD. Annealing was carried out at Salford University using an Steag AST 10 RTP
system, and at AMD using an Applied Materials RTP Radiance system. These are both
lamp based tools.
4.5.1 Salford Ultra Low Energy Implanter Laboratory
A schematic of the ULE implanter (11) is shown in Figure 4.23. The beamline
consists of three electrically isolated sections; the ion source, beam transport, and target
chamber. Two Applied Materials ion source assemblies are located symmetrically about
a mass analysing magnet. The ion sources used are the Bernas type, fitted with ovens
for solid source materials and also several gas inputs. The sources have a triode
extraction system, with adjustable gap and lateral alignment, which can adjust the
profile of the beam.
Beams are selected by focusing them through an adjustable mass resolving slit
located beyond the mass analysing magnet. Any neutrals present in the beam are
removed in a second magnet used to bend the beam through 5 º or 90 º into one of two
target chambers. For implantation the target chamber is used. The system comprises of
five stages of differential pumping so that pressures of ~ 10 -8 mbar are maintained in the
target chambers while the sources operate at ~ 10 -4 mbar. In the target chamber used for
the implants is a target mount attached to a precision goniometer with one rotational and
three directional degrees of freedom. At the final stage a low fill factor deceleration lens
is located directly in front of the target. The lens allows beams to be transported at
higher energies (5 – 15 keV) before being decelerated at the target to energies as low as
20 eV. This set up is called accel – decel mode, also referred to as retard mode.
Alternatively the transport and target sections may be electrically coupled so that ions
100